The present invention relates to an airbag apparatus that protects an occupant from an impact by deploying and inflating an airbag at a position close to the occupant seated in a vehicle seat when an impact due to, for example, a collision is applied to a vehicle.
An airbag apparatus is effective for protecting an occupant from an impact when an impact due to, for example, a collision is applied to a vehicle. The airbag apparatus includes an airbag that is formed into a bag shape and an inflator that supplies inflation gas into the airbag.
As a form of the airbag apparatus, a side airbag apparatus that protects an occupant from an impact due to, for example, a side collision has been proposed. In the side airbag apparatus, the airbag is installed in, for example, a backrest of a vehicle seat in a folded state together with an inflator. In the side airbag apparatus, when an impact is applied from the side on a member forming the side portion of a vehicle (body side portion) such as a side door, inflation gas is supplied from the inflator into the airbag. The inflation gas deploys and inflates the airbag, and a portion of the airbag is projected from the vehicle seat with a portion of the airbag remaining in the backrest. The airbag is then deployed and inflated forward of the vehicle from the backrest in a narrow space between the occupant seated in the vehicle seat and the body side portion. The deployed and inflated airbag is located between the occupant and the body side portion that bulges inward to restrain the occupant, and reduces the impact from the side transmitted to the occupant via the body side portion.
As forms of the above-mentioned side airbag apparatus, various apparatuses having a function to adjust the internal pressure of the airbag have been proposed.
For example, a side airbag apparatus disclosed in Japanese Laid-Open Patent Publication No. 2012-46167 includes an airbag 101 that is inflated by inflation gas as shown in FIG. 14. The inflation portion of the airbag 101 is divided by a partitioning member 102 into an upstream inflation portion 103, to which the inflation gas from the inflator is supplied, and a downstream inflation portion 104, to which the inflation gas is supplied via the upstream inflation portion 103.
Part of the partitioning member 102 forms a pair of overlapping portions 105, which overlaps each other in a band-like shape, in the upstream inflation portion 103. The overlapping portions 105 are joined by a joint portion 107 at a boundary between the overlapping portions 105 and non-overlapping portions 106 that are not overlapped.
The partitioning member 102 includes an opening 108, which is formed when the joint of the overlapping portions 105 by the joint portion 107 is partially cancelled, and a pressure regulating valve 110, which includes a pair of valve bodies 109 that sandwich the opening 108.
Before the upstream inflation portion 103 restrains the occupant, the pressure regulating valve 110 is closed by the valve bodies 109 that are pushed against each other in the upstream inflation portion 103 by the inflation gas. Thus, the internal pressure of only the upstream inflation portion 103 of the inflation portion is increased, and the upstream inflation portion 103 is deployed and inflated.
Also, when the upstream inflation portion 103 restrains the occupant, external force generated by the restraint flexes the valve bodies 109 via the partitioning member 102 and partially separates the valve bodies 109 from each other, so that the pressure regulating valve 110 is opened. The opening of the pressure regulating valve 110 causes the inflation gas in the upstream inflation portion 103 to flow out into the downstream inflation portion 104 via the opening 108. Accordingly, the internal pressure of the downstream inflation portion 104 is increased as the internal pressure of the upstream inflation portion 103 is reduced, and the downstream inflation portion 104 is deployed and inflated.
Thus, the above-mentioned operation of the pressure regulating valve 110 causes the property of load applied to the occupant via the airbag 101 to become suitable for appropriately restraining and protecting the occupant. That is, the property of load reaches a predetermined value in a short period of time and is subsequently maintained at the predetermined value.